<html>
  <body>
  <head>
    <meta name="description" content="Test for Battery Status API"/>
    <title>Battery Status API</title>
  </head>
  <body>
    <table>
      <tr>
        <td>Battery Status API</td>
        <td width="250px"></td>
      </tr>
      <tr>
        <td colspan="2">
          <hr>
        </td>
      </tr>
      <tr>
        <td>charging</td>
        <td id="charging"></td>
      </tr>
      <tr>
        <td>chargingTime</td>
        <td id="chargingTime"></td>
      </tr>
      <tr>
        <td>dischargingTime</td>
        <td id="dischargingTime"></td>
      </tr>
      <tr>
        <td>battery level</td>
        <td id="level"></td>
      </tr>
      <tr>
        <td colspan="2">
          <hr>
        </td>
      </tr>
      <tr>
        <td>promise status</td>
        <td id="promiseStatus"></td>
      </tr>
      <tr>
        <td>number of updates</td>
        <td id="numberUpdates"></td>
      </tr>
    </table>

    <script>
      var numberUpdates = 0;
      var battery;

      function batterySuccess(batteryManager) {
        battery = batteryManager;
        document.getElementById("promiseStatus").innerHTML = "success";
        updateBatteryInformation();
        battery.addEventListener('chargingchange', updateBatteryInformation);
        battery.addEventListener('chargingtimechange', updateBatteryInformation);
        battery.addEventListener('dischargingtimechange', updateBatteryInformation);
        battery.addEventListener('levelchange', updateBatteryInformation);
      }

      function batteryFailure() {
        document.getElementById("promiseStatus").innerHTML = "failed";
      }

      function ConvertToHMS(durationInSeconds) {
        if (!isFinite(durationInSeconds)) return "";
        var hours = Math.floor(durationInSeconds / 3600);
        var seconds = durationInSeconds % 60;
        var minutes = Math.floor((durationInSeconds - hours * 3600 - seconds) / 60);
        return " (" + hours + "h:" + minutes + "m:" + seconds + "s)";
      }

      function updateBatteryInformation() {
        document.getElementById("charging").innerHTML = battery.charging;
        document.getElementById("chargingTime").innerHTML = battery.chargingTime + ConvertToHMS(battery.chargingTime);
        document.getElementById("dischargingTime").innerHTML = battery.dischargingTime + ConvertToHMS(battery.dischargingTime);
        document.getElementById("level").innerHTML = battery.level;
        numberUpdates++;
        document.getElementById("numberUpdates").innerHTML = numberUpdates;
      }

      document.getElementById("promiseStatus").innerHTML = "pending";
      document.getElementById("numberUpdates").innerHTML = numberUpdates;
      navigator.getBattery().then(batterySuccess, batteryFailure);
    </script>
  </body>
</html>